LIVER CYTOSOLIC ALDEHYDE DEHYDROGENASES FROM ALCOHOL-DRINKING AND ALCOHOL-AVOIDING MOUSE STRAINS - PURIFICATION AND MOLECULAR-PROPERTIES

1. Liver cytosolic aldehyde dehydrogenases (AHD-2) have been isolated in a highly purified state from "alcohol-drinking" (C57BL/6J) and "alcohol-avoiding" (DBA/2J) strains of mice. 2. The purified enzymes were resolved into three major and one minor form of activity by isoelectric focusing (IEF) techniques and showed similar zymogram patterns. 3. The enzymes had identical subunit sizes on SDS-polyacrylamide gels: 53,000. 4. Gel exclusion chromatography, using Ultrogel AcA34, indicated that the enzymes were dimers. 5. The enzymes exhibited biphasic kinetic characteristics and were readily distinguished from each other. The purified forms of AHD-2 from C57BL/6J and DBA/2J mice exhibited two apparent Km values in each case: 10 .mu.M/100 .mu.M and 30 .mu.M/330 .mu.M respectively. 6. AHD-2 exhibited a broad pH optimum in the range 7.0-9.0 and was very sensitive towards disulpharum inhibiton, with 50% inhibition occurring at 0.17 .mu.M. 7. The kinetic results support proposals that AHD-2 may be the primary enzyme for oxidizing acetaldehyde during ethanol oxidation in vivo.